Prior art variable compression ratio engines have eccentric hinge pin expandable joints. These engines have hinge pins with off-set journals bearing for adjusting engine compression ratio. The prior art engines employ removable bearing caps for assembly of the eccentric hinge pins in the engine. A problem with these engines is that they would be expensive to manufacture and expensive to assemble due to the large number of bearing caps that need to be bolted together. A second problem is low mechanical stiffness and strength. The problem of low strength and stiffness is compounded in engines where the parting line of the bearing cap is oriented vertically rather than horizontally for best supporting the high mechanical forces encountered in internal combustion engines.
Eichi Kamiyama shows in U.S. Pat. No. 7,806,092 a variable compression ratio engine having an eccentric hinge pin assembly 25c, 25c1, 25c2, 25c3 and 25c4 retained in crankcase bearing caps 25a, 25a2 and jug bearing caps or bearing blocks 25b. Crankcase bearing caps 25a2 are bolted to crankcase 21, and jug bearing caps or bearing blocks 25b are bolted to jug 23. A problem with the invention taught in U.S. Pat. No. 7,806,092 is that it is expensive to manufacture and expensive to assemble due to the large number of bearing caps that need to be bolted to the jug and crankcase. A second problem is low mechanical stiffness and strength.
Per Gillbrand shows in U.S. Pat. No. 5,611,301 a variable compression ratio engine having an eccentric hinge pin 44 and removable bearing caps 46 and links 41. These components collectively result in a relatively large, heavy and expensive engine.